1078 



Li, C. P., B. Prescott, W. G. Jahnes,and E. C. Martino. 1962. 



Antimicrobial agents from mollusks. Trans. N.Y. Acad. Sci., Ser. II, 

 24(5): 504. 



Mereenaria (Venus) mereenaria is not mentioned. The original discovery 

 that commercial canned abalone juice had antiviral properties, and new 

 research that demonstrated antibacterial and antiviral activity in 

 extracts from abalone and oyster are described. These active substances 

 were designated paolin 1 and 2, from a Chinese word meaning abalone 

 extract. - J.L.M. 



1079 



Li, C. P., B. Prescott, E. C. Martino, and 0. C. Liu. 1968. 



Antineoplastic activity of clam liver extract. Nature 219(5159): 1163-1164. 



Average weight of a whole shucked Mereenaria mereenaria, including mantle 

 cavity fluids, was about 30 g and liver about 1 g. Final yield of dried 

 extracts was about 0.6% of wet liver or 0.02% of whole clam by weight. 

 Extraction procedure is described. When extracts were autoclaved or heated 

 at 100°C for 1 hr biological activity was destroyed. Mice were treated with 

 3 to 10 daily subcutaneous injections of extract in the left scapular region. 

 Mice were weighed before treatment and 7 days after implantation of leukaemic 

 cells. The treatment prolonged mean survival time of treated mice over 

 untreated controls. Ten additional preparations of clam liver extract were 

 tested, each according to a different schedule of treatment. Every 

 preparation showed definite antileukaemic activity. Extracts of whole clam, 

 including liver, also showed some activity. Preliminary studies showed that 

 other parts of the body also contained the active principle, but liver was 

 used because it was easy to dissect out and probably contained greatest 

 amounts of active material. The extract is not suggested as an antileukaemic 

 drug for man because it is toxic and its activity cannot match that of drugs 

 currently available, such as methotrexate. This drug was used in the 

 experiments described, and it usually increased mean survival time by 110% 

 or more. Antileukaemic activity in clam liver is an interesting phenomenon 

 and further study may provide useful implications. - J.L.M. 



1080 



Li, c. P., B. Prescott, B. E. Eddy, E. W. Chu, and E. C. Martino. 1968. 



Studies on inhibition of viral oncogenesis. I. Reduced tumor incidence in 

 hamsters inoculated with adenovirus 12 and treated with clam extracts. J. 

 Natl. Cancer Inst. 41(5): 1249-1253. 



Extracts of whole meats, or of liver (digestive diverticulum), of Mereenaria 

 mereenaria reduced incidence of tumor formation in hamsters induced by 

 adenovirus 12. A total amount of 63 to 85 mg/hamster of crude whole clam 

 extract, administered in 12 to 14 daily injections, was effective. Clam 

 liver extract was effective in much smaller doses (1.9 mg divided into 2 or 3 

 injections) . Clam extract may have suppressed tumor development by interfering 

 with the process of transformation of normal cells into malignant cells rather 

 than by inhibiting virus, or it may have acted directly on tumor cells which 

 had just been transformed. Both sexes of hamster responded to clam extract, 

 but males probably were more responsive. It was not certain whether reduction 

 of tumor formation was caused by non-specific toxicity of clam extract, which 

 retarded normal growth of hamsters and thus development of tumors. Further 

 work was in progress using another antitumor agent which does not affect 

 hamster growth. - J.L.M. 



301 



